JP2012108213A - Retroreflection mirror and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retroreflection mirror in which dark portion formed in a mountain part of a retroreflection element is made to be a special shape so that the design of appearance is improved and a manufacturing method of the mirror.SOLUTION: In a retroreflection mirror 3 in which multiple retroreflection elements 31 are arranged, the curvature radius rm of a mountain part 31m of the retroreflection elements 31 is made larger than the curvature radius rv of a valley part 31v. Light entering the mountain part 31m is transmitted or reflected to a wide range so that a bold Y shaped dark pattern is created, thereby improving the design appearance of the retroreflection mirror.

Description

  The present invention relates to a retroreflective mirror (hereinafter referred to as RR) in which a plurality of retroreflective elements (reflex / reflector elements: hereinafter referred to as RR elements) are arranged, and in particular, RR with improved appearance of reflected light and its appearance It relates to a manufacturing method.

  A vehicle such as an automobile or a bicycle is equipped with an RR that reflects light emitted from another vehicle toward the other vehicle. As this RR, for example, in Patent Document 1, a large number of right triangular pyramidal projections (part of a cube) are arranged as RR elements on the inner surface of a light-transmitting resin plate, and peaks and valleys are arranged in a matrix. The structure arranged in the above is used. In this RR, since the light incident from the outer surface side of the RR is totally reflected by the inner surface of the RR element, the light is reflected in the incident direction. In addition, this RR is formed by resin molding using a mold, and in manufacturing the mold, as in Patent Document 2, an electric power using a plurality of arrow-shaped pins whose tips are formed in the shape of an RR element is used. Casting methods have been used. Although the explanation about this electroforming method and the explanation about the method of resin molding RR using this mold are omitted, the shape of the arrow pin is directly reflected in the RR manufactured by this method. The RR element is formed in a shape having a corner with a sharp peak or valley, in other words, a curvature radius of the peak or valley is almost “0”.

JP-A-9-58336 JP 2005-125649 A

In this RR, when incident light is retroreflected, when the RR is viewed from the surface side, as shown in FIG. 4 (b), a large number of rhombus lines composed of ridge lines connecting peaks and valleys A dark pattern Pr is observed. In other words, the peak and valley are not expected to be totally reflected due to their cross-sectional shape, and retroreflection is difficult to perform, so the amount of retroreflected light in the region along the ridge line connecting these peaks and valleys is reduced. However, the ridgeline appears darker than the other areas. In the RR element in which the respective radii of curvature of the peaks and valleys are set to “0” as described above, the ridge line connecting the peaks and valleys is formed in a thin line shape. The observed dark pattern Pr can be seen only as a thin line having a rhombus shape. Therefore, the appearance of RR is limited to a simple pattern in which minute rhombuses are arranged, and it is not possible to obtain a highly designed RR having a unique appearance.

  An object of the present invention is to provide an RR with improved appearance design by making the shape of the dark part generated at least at the peak part of the RR element unique. Another object of the present invention is to provide a method for producing RR with improved design properties.

The present invention is an RR in which a large number of RR elements are arranged, wherein the curvature radius of the peak portion of the RR element is larger than the curvature radius of the valley portion. Further, when the RR elements are arranged on a curved surface, the optical axis of each RR element is changed stepwise along the curved surface. Alternatively, the RR elements are divided into a plurality of groups along the curved surface, the optical axes of the RR elements in each group are in the same direction, and the optical axes of the RR elements in different groups change stepwise along the curved surface. The configuration is as follows.

  In the present invention, when manufacturing RR, a mold is manufactured by directly carving a molding surface for molding RR with a cutting tool having a tip having a required radius of curvature, and an injection molding method using the mold is used. RR is formed.

  According to the RR of the present invention, the amount of light reflected in the light incident direction at the peak of the RR element is reduced, so that when the RR is observed from the outer surface, a Y-shaped dark pattern centered on the peak can be observed. Thus, the Y-shaped dark pattern can improve the design of the appearance of the RR. In particular, when the RR is formed on a curved surface, by changing the optical axis of the RR element stepwise along the curved surface, it is possible to visually recognize the light reflection of the RR from a wide range and to improve the appearance at each observation position. Can be improved.

Further, in the RR manufacturing method of the present invention, the RR is formed by the injection molding method using a mold in which the molding surface is directly carved by a cutting tool having a tip portion having a required radius of curvature. It becomes easy to manufacture a mold for manufacturing the RR, and the RR of the present invention can be easily manufactured by using the mold.

The perspective view which fractured | ruptured a part of rear combination lamp to which RR of this invention was applied. The perspective view of a part of RR and its enlarged sectional view and optical path diagram. Sectional drawing of the molding die of RR, and a figure explaining a manufacturing process. The figure which shows typically the external appearance of Embodiment 1 and each conventional RR. Sectional drawing of Embodiment 2. FIG. Sectional drawing of Embodiment 3. FIG.

(Embodiment 1)
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of Embodiment 1 in which the RR of the present invention is applied to a rear combination lamp of an automobile. The lamp housing 1 of the rear combination lamp RCL has a structure in which a front cover 12 functioning as an optical lens is mounted on the front surface (surface on the rear side of the automobile) of a shallow dish-shaped lamp body 11 having a required front shape. A backup lamp BUL, a turn signal lamp TSL, and a tail & stop lamp T & SL are disposed in the housing 1. In other words, partition walls 13 are provided on the inner surface of the lamp body 11 corresponding to the lamps BUL, TSL, T & SL, and the regions of the lamps are partitioned by the partition walls 13. A light source 2 is provided in each lamp region in the lamp body 11. Here, each light source 2 has a configuration in which an LED (light emitting diode) 22 is mounted on a wiring board 21.

The front cover 12 has a configuration in which a red lens 12R, an amber lens 12U, and a white lens (not shown in the drawing) are formed in correspondence with these lamps, and these lenses are integrated. Further, the front cover 12 is formed with an RR3 that is an object of the present invention in a part of a region where the red lens 12R is partitioned. The RR 3 is integrally formed on the inner surface of the front cover 2 with a large number of RR elements 31 arranged in a matrix. Needless to say, the RR 3 is configured to reflect the illumination light of the following vehicle toward the following vehicle by the RR elements 31.

The RR3 is formed by molding a red light-transmitting resin. As shown in FIG. 2 (a), an external perspective view is shown, and the outer surface 3a directed downward is a smooth surface. The RR element 31 is formed on the inner surface 3b formed and directed upward. The RR element 31 has a regular hexahedron (cube) with a corner 31m as a ridge 31m, and is formed as a right triangular pyramid-shaped projection having three faces with the ridge 31m as a vertex. A plurality of RR3s are arranged in the vertical and horizontal directions. The cross-sectional shape obtained by cutting the RR3 in one direction, for example, the direction in which the peak portions 31m of the RR element 31 are continuous, has a plurality of RR elements 31 each having a peak portion 31m having a right triangle as shown in FIG. Thus, the valley portion 31v having the lowest height is formed between the adjacent RR elements 31.

  As the shape of the RR element 31, in the first embodiment, the height dimension from the valley 31v to the peak 31m of the RR element 31 is 2 mm, the skirt dimension of the RR element 31, in other words, the interval between the adjacent valleys 31v. Is formed in each dimension of 2.5 mm. Further, when the RR element 31 is formed in this way, the curvature radius rv of the valley portion 31v is configured to be 0 mm. That is, the valley portion 31v of the RR element 31 is formed in an angular shape in which a ridge line connecting the peak portion 31m and the valley portion 31v of the RR element 31 intersects at a substantially right angle. On the other hand, the peak portion 31m of the RR element 31 has a radius of curvature rm larger than the radius of curvature rv of the valley portion 31v, in this case, any size in the range of 0.1 to 0.3 mm. The peak portion 31m of the element 31 is formed in a shape close to a spherical surface. In addition, since the ridge line part each extended toward the three-way valley part 31v from the one mountain part 31m is also formed in the curvature radius rm similar to the mountain part 31m here, in the following description, these ridge line parts are referred to as the mountain part. It is included in 31m.

The RR 3 having this configuration is formed by molding a light-transmitting red resin using a mold. As shown in FIG. 3 (a), a mold 4 comprising a lower mold 41 having a right triangle triangular RR element recess 43 for molding an RR element and an upper mold 42 having an inner surface formed as a flat surface. The RR3 is molded by an injection molding method in which a red resin is injected into the cavity 44 constituted by both molds. The mold 4, particularly the lower mold 41 having the RR element recess 43, is not the electroforming method disclosed in Patent Document 2, but a molding surface having a configuration in which a large number of the RR element recesses 43 are arranged by cutting the surface of the mold material. Is manufactured by a so-called direct engraving method. In this direct engraving method, for example, an RR element concave portion 43 is formed on a flat mold surface using a cutting tool, and the molding surface is finished to a mirror surface simultaneously with the cutting. By finishing the molding surface as a mirror surface in this way, when RR3 is resin-molded using the mold, the surface of the molded RR3 is formed into a smooth surface, and it is possible to mold RR with high light transmittance. become. Thereby, a die can be manufactured at a low cost and in a short time compared with the electroforming method, and further, RR can be manufactured.

  For example, as shown in the schematic cross-sectional view of FIG. 3B, when forming the molding surface of the RR element recess 43 in the direct engraving method, the radius of curvature of the tip 5a is 0.1 to 0.3 mm. A cutting tool 5 having a spherical shape is used. When cutting the molding surface of the RR element recess 43, the bottom portion 43a is brought into contact with the portion corresponding to the peak portion 31m of the RR element 31, that is, the bottom portion 43a of the molding surface, by cutting the tip 5a of the cutting tool 5. The cutting tool 5 is formed in a shape that follows the radius of curvature of the tip 5a. Further, the cutting tool 5 is linearly moved along the inclined surface of the RR element recess 43 for cutting, whereby the top 43b of the molding surface corresponding to the valley 31v of the RR element 31 intersects with a linear ridge line. Formed into a square shape. Needless to say, the upper mold 42 corresponding to the outer surface of the RR 3 paired with the lower mold 41 is formed on a flat mirror surface.

  By forming the cavity 44 using the mold 4 thus manufactured and injecting a light-transmitting red resin into the cavity 44, the molding of the RR3 can be realized. An injection molding method is used for this molding. As shown in FIG. 3A, the bottom 43a of the RR element recess 43 has a spherical shape with the radius of curvature described above, so that the resin is injected into the cavity 44. In this case, the air in the cavity 44 flows more easily along the molding surface than the mold having the bottom 43a having a square shape, and the air venting efficiency in the cavity 44 is increased so that voids (bubbles) in the molded RR3 are formed. Effective in preventing the occurrence. Further, since the bottom portion 43a of the molding surface is a spherical surface, the mold release resistance when releasing the RR3 after molding becomes smaller than that of the square shape, and the mold release property of the RR3 is also improved. Note that FIG. 3A is a diagram in the case where only RR3 is molded to simplify the explanation, but in reality, since RR3 is integrally formed with the front cover 12, the structure of the mold is complicated. It becomes.

  In the formed RR3, as shown in FIG. 2C, the light incident from the outer surface of the RR3 is totally reflected by the inner surface of the RR element 31, and then the light is incident in the opposite direction of 180 degrees from the outer surface of the RR3. It is emitted toward the direction. At this time, when RR3 is observed from the outer surface, the entire surface of RR3 appears bright. However, since the valley portion 31v of the RR element 31 has a square shape with a radius of curvature of “0”, the valley portion 31v has a ridge line of the RR element 31. Darken along the line. This linear darkness is the same as the conventional RR. However, since the peak portion 31m of the RR element 31 has a radius of curvature larger than that of the valley portion 31v, a part of the light incident on the peak portion 31m is transmitted as shown in FIG. Since the portion is reflected toward a wide range, the reflected light in the incident direction is reduced, and a region having a width of about twice the radius of curvature of the peak portion 31m, in this embodiment, a region of about 0.2 to 0.6 mm. Becomes darker.

As a result, as schematically shown in FIG. 4A, a thin linear dark pattern Pv is observed in the valley portion 31v of the RR element 31, but the peak portion 31m extends to a ridge line portion toward the valley portion 31v. A Y-shaped thick dark pattern Pm is observed in the region. That is, the entire RR3 appears to have a large number of Y-shaped dark patterns Pm arranged in a matrix. Since this Y-shaped dark pattern Pm is thick, it can be sufficiently viewed from a distance. Thus, in this RR3, only the narrow dark pattern Pv whose entire surface is a simple shape as in the prior art. From the appearance, in addition to this dark pattern Pv, a Y-shaped thick dark pattern Pm is scattered, so that the design of the appearance of RR3 can be improved.

  Here, if the radius of curvature of the peak portion 31m of the RR element 31 is smaller than this, the effect of increasing the line width of the Y-shaped dark pattern Pm cannot be expected, and the dark pattern Pm The visibility is lowered and the effect of improving the appearance of RR3 is small. Further, if the curvature radius of the peak portion 31m is larger than this, it is effective in increasing the line width of the dark pattern Pm, but the area of the reflection surface effective for light reflection of the RR element 31 is reduced accordingly. As a result, the light reflection efficiency of RR3 is reduced. Further, it goes without saying that the radius of curvature of the above-described peak portion 31m is appropriately changed according to the difference in the height dimension and the skirt dimension of the RR element 31.

(Embodiment 2)
In the first embodiment, the RR is an example of a flat plate, but the RR disposed in the car body corner of the automobile reflects light in the light range from the rear to the side of the host vehicle. An RR capable of confirming light reflection of the RR from a wide range may be required. For example, FIG. 5 shows an example of the RR 3A disposed at the rear corner of the automobile, which is formed in a curved shape from the rear of the automobile toward the side surface. A large number of RR elements 311 to 316 are arranged on the inner surface of the RR 3A. The RR elements adjacent to the RR elements 311 to 316 in the horizontal direction have their optical axes x1 to x6 changed in direction. ing. Here, if it is defined that the optical axis of the RR element is a straight line that passes through the apex of the peak of the RR element and is at an equal distance from three orthogonal surfaces, the optical axes x1 to x6 of the RR elements 311 to 316 are Following the curved surface shape of the outer surface, the structure is gradually changed from the rear of the vehicle toward the side surface. Further, each RR element 311 to 316 is formed as a spherical surface in which the curvature radius of the peak portion is larger than the curvature radius of the valley portion, as in the above embodiment.

  In the RR3A according to the second embodiment, light incident on the RR3A from a wide range of directions extending from the rear to the side of the automobile has an optical axis x1 to x6 directed in a direction close to the direction in which the light is incident. Since the light is reflected by 311 to 316 in the direction opposite to the direction in which the light is incident, the light reflection by RR3A can be confirmed. At this time, in each of the RR elements 311 to 316, since the peak portion is formed as a spherical surface, the portion of the required size range from the peak portion to the valley portion of the RR elements 311 to 316 is a thick line shape. As shown in FIG. 4A, it appears as a dark Y-shaped pattern. This dark pattern is the same as the dark pattern Pm of the first embodiment, and since it has a large width, it can be sufficiently visually recognized from a distance, and the design of the appearance of the RR3A is different from that of the first embodiment. Can be improved.

(Embodiment 3)
The RR formed in a curved surface shape as in the second embodiment may be configured as RR3B as shown in FIG. In this RR3B, a large number of RR elements are divided into a plurality of groups for each required width region along the curved surface, and the optical axis x1 of each RR element in the same group, for example, three adjacent RR elements 311 is in the same direction. In other words, the optical axes x2 and x3 of the RR elements 312 and 313 of other groups arranged along the curved surface are configured to gradually change along the curved surface. Needless to say, each RR element 311, 312, 313 is formed as a spherical surface in which the curvature radius of the peak portion is larger than the curvature radius of the valley portion, as in the above embodiment.

  In the RR3B having this configuration, light incident on the RR3B from a predetermined direction is in a direction opposite to the direction in which the light is incident by each RR element of the group in which the optical axis is directed in a direction close to the direction in which the light is incident. Reflected towards. In the RR elements 311 to 313, since the crest is formed as a spherical surface, the portion of the required dimension range from the crest to the trough of the RR element that performs light reflection is the same as shown in FIG. It looks like a dark Y-shaped pattern. In particular, in this RR, since such a dark pattern is observed in all the RR elements in the group where light is reflected, the design of the appearance of the RR is improved in a form different from the first and second embodiments. Can do.

  In the second and third embodiments, the example in which the RR is formed in a curved surface bent in the horizontal direction is shown, but the present invention can be similarly applied even when the RR is formed in a curved surface bent in the vertical direction. is there. In this case, the optical axes of the RR elements arranged in the vertical direction may be configured to change in the vertical direction in units of one unit or in units of groups. With this RR, it becomes possible to visually recognize the light reflection at the RR over a wide range in the vertical direction. The same applies to RR bent in both the horizontal direction and the vertical direction, and the optical axis of each RR element may be configured to change in the horizontal direction and the vertical direction.

  In Embodiments 1 to 3, the case where the radius of curvature of the valley portion of the RR element is “0” has been described. However, if the radius of curvature is increased, the area of the effective reflection surface when light is reflected at the RR is reduced as in the case of the mountain portion, and the light reflection efficiency of the RR is reduced. Moreover, the width dimension of the dark pattern observed in the valley portion of RR becomes large and becomes mixed with the dark pattern observed in the mountain portion, and the appearance of RR may be lowered. Therefore, it is necessary to set an appropriate curvature radius in consideration of the relationship with the curvature radius of the peak portion.

  The present invention is not limited to RR molded using a die formed by direct engraving, and can also be applied to RR molded using a die formed by electroforming. However, when a metal mold is manufactured by electroforming, it is necessary to configure so that the radius of curvature of the peak portion of the RR element can be controlled.

  The RR of the present invention is not limited to the RR disposed on the rear surface of the rear combination lamp shown in the embodiment, and may be configured as a rear side RR disposed on the side surface of the rear combination lamp. Further, it may be configured as a front side RR formed integrally with a vehicle headlamp, or may be configured as an RR formed integrally with a rear side marker lamp or a front side marker lamp. Furthermore, it is also possible to configure as a rear RR with a bumper as an independent RR.

  The present invention can be applied to an RR configured by arranging a large number of RR elements.

1 Lamp Housing 2 Light Source 3 RR (Retroreflector)
4 Die 5 Cutting Tool 31 RR Element 31m Mountain 31v Valley 41 Lower Die 42 Upper Die 43 RR Element Recess 44 Cavity Pm Dark Pattern Pv Valley Dark Pattern

Claims (4)

  A retroreflective mirror in which a large number of retroreflective elements are arranged, wherein the radius of curvature of the peak portion of the retroreflective element is larger than the radius of curvature of the valley portion.   The retroreflective mirror according to claim 1, wherein the retroreflective elements are arranged on a curved surface, and an optical axis of each retroreflective element is changed stepwise along the curved surface.   The retroreflective elements are divided into a plurality of groups along the curved surface, the optical axes of the retroreflective elements of each group are in the same direction, and the optical axes of the retroreflective elements of different groups are stepped along the curved surface. The retroreflector according to claim 2, wherein the retroreflector is changed to: It is a manufacturing method of the retroreflective mirror in any one of Claims 1-3, Comprising: A molding surface is directly carved with the cutting tool which has a front-end | tip part of a required curvature radius, and this metal mold | die was used. A method of manufacturing a retroreflective mirror, comprising forming the retroreflective mirror by an injection molding method.

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